Objective To evaluate the efficacy and safety of Cidan Capsule combined with adjuvant transarterial chemoembolization (TACE) in patients with a high risk of early recurrence after curative resection of hepatocellular carcinoma (HCC). Methods A multicenter, randomized controlled trial was conducted in patients with high-risk recurrence factors after curative resection of HCC from 9 medical centers between July 2014 and July 2018. Totally 249 patients were randomly assigned to TACE with or without Cidan Capsule administration groups by stratified block in a 1:1 ratio. Postoperative adjuvant TACE was given 4-5 weeks after hepatic resection in both groups. Additionally, 125 patients in the TACE plus Cidan group were administrated Cidan Capsule (0.27 g/capsule, 5 capsules every time, 4 times a day) for 6 months with a 24-month follow-up. Primary endpoints included disease-free survival (DFS) and tumor recurrence rate (TRR). Secondary endpoint was overall survival (OS). Any drug-related adverse events (AEs) were observed and recorded. Results As the data cutoff in July 9th, 2018, the median DFS was not reached in the TACE plus Cidan group and 234.0 days in the TACE group (hazard ratio, 0.420, 95% confidence interval, 0.290-0.608; P<0.01). The 1- and 2-year TRR in the TACE plus Cidan and TACE groups were 31.5%, 37.1%, and 60.8%, 63.4%, respectively (P<0.01). Median OS was not reached in both groups. The 1- and 2-year OS rates in TACE plus Cidan and TACE groups were 98.4%, 98.4%, and 89.5%, 87.9%, respectively (P<0.05). The most common grade 3-4 AEs included fatigue, abdominal pain, lumbar pain, and nausea. One serious AE was reported in 1 patient in the TACE plus Cidan group, the death was due to retroperitoneal mass hemorrhage and hemorrhagic shock, and was not related to study drug. Conclusions Cidan Capsule in combination with TACE can reduce the incidence of early recurrence in HCC patients at high-risk of recurrence after radical hepatectomy and may be an appropriate option in postoperative anti-recurrence treatment. (Registration No. NCT 02253511)